7. An element is any substance that contains one type of
a. milecule.
b. isotope.
c. atom.
d. proton.

c. atom. (p. 17)

8. The differences between one polypeptide and another lies in
a. the type of peptide bond thay contain.
b. the type of sugar they contain.
c. whether they are saturated or not.
d. the sequence of amino acids.

d. the sequence of amino acids. (p. 27)

9. An ion is an atom or milecule that
a. is in a gaseous state.
b. carries an electrical charge.
c. is attracted to a north-seeking pole.
d. forms a visible glow.

b. carries an electrical charge. (p. 18)

10. The positively charged particles in the nucleus of an atom are
a. neutrons.
b. electrons.
c. protons.
d. isotopes.